阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。
Mrs. Black has three sons. They’re Mike, Dave and Jeff. Mike is eleven years old. He’s the(1)________(young)of the three children. He looks as(2)_______ (tall) as his brother Dave. But he is a little (3)________(heavy) than Dave. Mike and Dave both like (4)________(run) . Dave is thinner than Mike, so he runs much (5)________(fast) than Mike. The two boys also like one of the most dangerous (6)________ (sport), mountain climbing. Every weekend they go mountain climbing. Sure, every time Dave gets to the top of the mountain(7)_______(early) than Mike.
Jeff is the(8)_________(old) and the most serious child of the three children. He hardly ever talks but I think he does things more carefully than any other student in our class. In every test he always does best but I do (9)________ (badly). Jeff always tries his best to help me. Jeff is the (10)_______wonderful boy that I’ve met so far.I like him. And I’m proud to be his friend.